Guide: How to Establish your Base-Line IGF-I (Serum) in Order to Determine Dose/Response (ΔIGF-I) to Agents that Increase IGF-I (e.g., rhGH)

Type-IIx · Oct 5, 2023

Establishing a Base-Line Serum IGF-I Value
Author: Type-IIx

Intent: (1) To help users establish a base-line serum IGF-I value In order to form a meaningful basis for comparison of serum IGF-I changes to base-line. (2) To help prospective clients (i.e., Comprehensive Coaching [training + nutrition + PEDs + supplements], or Individualized Protocols [PEDs + supplements]) have this data ready even before intake, so that we can get straight to the work of determining their drug response and forego superfluous periods of management of wash-out from agents that affect IGF-I levels.

The user must request bloodwork for serum IGF-I under conditions of total washout from agents that affect IGF-I levels (time spent at either TRT if the user does not intend to restore physiologic testosterone secretion, or after recovery to normal endogenous testosterone levels). The following enumerated list (non-exhaustive) describes the procedures to ensure wash-out for bodybuilding agents in common use:

1. RhGH and/or GH secretagogues (i.e., Ghrelin mimetics, Growth hormone-releasing hormone agonists): After a minimum of 12 weeks after cessation (total abstinence) from rhGH and/or GH secretagogues, but ideally, if feasible, and time on > 12 weeks, then time off [washout period] = time on (e.g., if finishing up a 6 month or 24 week course of rhGH, request bloodwork for serum IGF-I after 24 weeks without any administration of rhGH; if this is impracticable, then, 12 weeks after cessation, or time off [washout period] = 12 weeks), and/or

2. Aromatizing androgen (e.g., testosterone, nandrolone [Deca durabolin, NPP], boldenone [Equipoise], methandienone [Dianabol], MENT [Trestolone], methyltestosterone) and stanozolol [Winstrol, Stromba]: After a minimum duration required for total aromatizing androgen (e.g., Test, Deca/NPP, EQ, Dbol, MENT, Methyltest) and/or Winstrol/Stromba washout. This time-course depends primarily on the ester side-chain length (i.e., duration of activity) of a parenteral (i.m.) oil-based preparation, e.g., undecanoate and undecylenate esters take months to reach washout after medium-term use (e.g., 10 – 26 week cycles), whereas enanthate and cypionate esters take weeks and 17AA oral drugs take days. Mathematical formulae and freely available graphing tools are available to plot the time-course of wash-out from specified preparations, doses, and administration schedule (e.g., SteroidPlotter).

Durations of Activity (parenteral; i.m. preparations):
- propionate: 2 days
- phenylpropionate: 10 days
- enanthate, cypionate, cyclohexane carboxylate: 15 days (2 weeks)
- hexahydrobenzylcarbonate: 20 days (3 weeks)
- decanoate: 28 days (4 weeks)
- undecylenate: 56 days (8 weeks)
- undecanoate: 84 days (12 weeks)
Durations of Activity (oral, 17α-alkylated (“17AA”); p.o. preparations):
- stanozolol: 4 days
- everything else: 1 – 2 days
General Rule: After drug clearance (time off = duration of activity ≈ 4 * t1/2), a period of about 1 additional week should be taken to tamp down pharmacodynamic effects on aromatase before requesting bloodwork (time off [washout period] = duration of activity + 1 week), and/or

3. Selective Estrogen Receptor Modulators (SERMs; particularly enclomiphene citrate [Clomid]) and Aromatase Inhibitors (AIs; though exemestane [Aromasin] has not been shown to affect IGF-I at doses up to 50 mg/d for 10 days): Determining the minimum duration required for washout of each drug requires reference to each drug’s pharmacodynamic effects on serum IGF-I, where available. SERM drugs in particular (especially Clomid) tend to reduce serum IGF-I due to antagonism of ER in hypo-thalamo brain regions where activity is linked also to GH secretion, thereby reducing GH signaling to the liver somatotrophs to secrete IGF-I. If pharmacodynamic effects on IGF-I are known but not well described with respect to time-course, then the user should fall back on the same General Rule as for aromatizing androgen – i.e., time off [wash-out] = duration of activity + 1 week should be taken to tamp down pharmacodynamic effects on aromatase before requesting bloodwork, and/or

4. Gonadotropins (hCG, hMG): HCG is a long-acting LH analogue with a duration of activity of 3 days. HMG, as bioidentical LH & FSH, is short-acting with a duration of activity of 1 – 2 days. After single doses of 1,500 IU & 6,000 IU hCG, blood estradiol levels had not returned to base-line after 6 days for the 6,000 IU dose; but did so for the lower doses of 1,500 IU, 375 IU, and 93.75 IU. The General Rule, then, applies to the use of hCG with or without combination with hMG – total wash-out (pharmacokinetics of duration of activity; here, 3 days) plus 1 additional week (i.e., time off [washout period] = 10 days) should be taken to tamp down pharmacodynamic effects on aromatase (testicular) before requesting bloodwork, and/or

5. Insulin (e.g., glargine), Sulfonylureas (e.g., glimepirid): While it is well-established that insulin per se potently increases serum IGF-I & bioavailability, and insulin glargine (e.g., Lantus) in particular potently activates IGF-IR directly, total washout from insulin preparations are particularly important to establish a valid base-line IGF-I measure. Since the bioactivity of various insulin preparations differ by formulation considerably with respect not only to pharmacokinetics but indeed mitogenic (growth) and metabolic effects, IGF-I receptor (IGF-IR) action, and pharmacodynamic effects on IGF-I secretion and bioavailability (i.e., by freeing up more bioactive IGF-I fractions vs. those in ternary complexes with the acid-labile subunit [ALS]), a Prudent Approach is strongly advised for washing out from exogenous insulin preparations:

Prudent Approach: After drug clearance (time off = duration of activity ≈ 4 * t1/2) from the longest-duration insulin preparation or sulfonylurea in use, a minimum of an additional 12 weeks after drug clearance (total abstinence) from the insulin preparation or sulfonylurea in use, but ideally, if feasible and if time on > 12 weeks, washout = drug clearance + time on (e.g., if finishing up a 6 month or 24 week course of glimepirid (duration of activity = 6 days), request bloodwork for serum IGF-I after 25 weeks without any administration of glimepirid; if this is impracticable, then, after 13 weeks without any administration of glimepirid.

6. Estrogens & Progestins (e.g., ethylestrenol, norgestrel): Data Needed; since these hormonal (e.g., contraceptive) agents reduce bioavailable IGF-I by increasing IGF-binding protein 1 (IGFBP-1), thereby unleashing GH secretion by feedback withdrawal – inducing a state of GH resistance – it is imperative that they are totally washed out from to establish a valid base-line serum IGF-I. The General Rule + an additional 10 days applies, formulation-dependently, to theoretically counter the unknown duration of biological activity of IGFBP-1.

Application:

If stopping all agents that affect IGF-I levels at the same time, then the agent that requires the longest washout period dictates the total duration of washout. That is, these agents affect IGF-I in parallel rather than in series, such that the user may wash out from all agents synchronously (at the same time) rather than one after another.

Keefs · Oct 5, 2023

Type-IIx said:
Establishing a Base-Line Serum IGF-I Value
Author: Type-IIx

Intent: (1) To help users establish a base-line serum IGF-I value In order to form a meaningful basis for comparison of serum IGF-I changes to base-line. (2) To help prospective clients (i.e., Comprehensive Coaching [training + nutrition + PEDs + supplements], or Individualized Protocols [PEDs + supplements]) have this data ready even before intake, so that we can get straight to the work of determining their drug response and forego superfluous periods of management of wash-out from agents that affect IGF-I levels.

The user must request bloodwork for serum IGF-I under conditions of total washout from agents that affect IGF-I levels (time spent at either TRT if the user does not intend to restore physiologic testosterone secretion, or after recovery to normal endogenous testosterone levels). The following enumerated list (non-exhaustive) describes the procedures to ensure wash-out for bodybuilding agents in common use:

1. RhGH and/or GH secretagogues (i.e., Ghrelin mimetics, Growth hormone-releasing hormone agonists): After a minimum of 12 weeks after cessation (total abstinence) from rhGH and/or GH secretagogues, but ideally, if feasible, and time on > 12 weeks, then time off [washout period] = time on (e.g., if finishing up a 6 month or 24 week course of rhGH, request bloodwork for serum IGF-I after 24 weeks without any administration of rhGH; if this is impracticable, then, 12 weeks after cessation, or time off [washout period] = 12 weeks), and/or

2. Aromatizing androgen (e.g., testosterone, nandrolone [Deca durabolin, NPP], boldenone [Equipoise], methandienone [Dianabol], MENT [Trestolone], methyltestosterone) and stanozolol [Winstrol, Stromba]: After a minimum duration required for total aromatizing androgen (e.g., Test, Deca/NPP, EQ, Dbol, MENT, Methyltest) and/or Winstrol/Stromba washout. This time-course depends primarily on the ester side-chain length (i.e., duration of activity) of a parenteral (i.m.) oil-based preparation, e.g., undecanoate and undecylenate esters take months to reach washout after medium-term use (e.g., 10 – 26 week cycles), whereas enanthate and cypionate esters take weeks and 17AA oral drugs take days. Mathematical formulae and freely available graphing tools are available to plot the time-course of wash-out from specified preparations, doses, and administration schedule (e.g., SteroidPlotter).

Durations of Activity (parenteral; i.m. preparations):

propionate: 2 days

phenylpropionate: 10 days

enanthate, cypionate, cyclohexane carboxylate: 15 days (2 weeks)

hexahydrobenzylcarbonate: 20 days (3 weeks)

decanoate: 28 days (4 weeks)

undecylenate: 56 days (8 weeks)

undecanoate: 84 days (12 weeks)

Durations of Activity (oral, 17α-alkylated (“17AA”); p.o. preparations):

stanozolol: 4 days

everything else: 1 – 2 days

General Rule: After drug clearance (time off = duration of activity ≈ 4 * t1/2), a period of about 1 additional week should be taken to tamp down pharmacodynamic effects on aromatase before requesting bloodwork (time off [washout period] = duration of activity + 1 week), and/or

3. Selective Estrogen Receptor Modulators (SERMs; particularly enclomiphene citrate [Clomid]) and Aromatase Inhibitors (AIs; though exemestane [Aromasin] has not been shown to affect IGF-I at doses up to 50 mg/d for 10 days): Determining the minimum duration required for washout of each drug requires reference to each drug’s pharmacodynamic effects on serum IGF-I, where available. SERM drugs in particular (especially Clomid) tend to reduce serum IGF-I due to antagonism of ER in hypo-thalamo brain regions where activity is linked also to GH secretion, thereby reducing GH signaling to the liver somatotrophs to secrete IGF-I. If pharmacodynamic effects on IGF-I are known but not well described with respect to time-course, then the user should fall back on the same General Rule as for aromatizing androgen – i.e., time off [wash-out] = duration of activity + 1 week should be taken to tamp down pharmacodynamic effects on aromatase before requesting bloodwork, and/or

4. Gonadotropins (hCG, hMG): HCG is a long-acting LH analogue with a duration of activity of 3 days. HMG, as bioidentical LH & FSH, is short-acting with a duration of activity of 1 – 2 days. After single doses of 1,500 IU & 6,000 IU hCG, blood estradiol levels had not returned to base-line after 6 days for the 6,000 IU dose; but did so for the lower doses of 1,500 IU, 375 IU, and 93.75 IU. The General Rule, then, applies to the use of hCG with or without combination with hMG – total wash-out (pharmacokinetics of duration of activity; here, 3 days) plus 1 additional week (i.e., time off [washout period] = 10 days) should be taken to tamp down pharmacodynamic effects on aromatase (testicular) before requesting bloodwork, and/or

5. Insulin (e.g., glargine), Sulfonylureas (e.g., glimepirid): While it is well-established that insulin per se potently increases serum IGF-I & bioavailability, and insulin glargine (e.g., Lantus) in particular potently activates IGF-IR directly, total washout from insulin preparations are particularly important to establish a valid base-line IGF-I measure. Since the bioactivity of various insulin preparations differ by formulation considerably with respect not only to pharmacokinetics but indeed mitogenic (growth) and metabolic effects, IGF-I receptor (IGF-IR) action, and pharmacodynamic effects on IGF-I secretion and bioavailability (i.e., by freeing up more bioactive IGF-I fractions vs. those in ternary complexes with the acid-labile subunit [ALS]), a Prudent Approach is strongly advised for washing out from exogenous insulin preparations:

Prudent Approach: After drug clearance (time off = duration of activity ≈ 4 * t1/2) from the longest-duration insulin preparation or sulfonylurea in use, a minimum of an additional 12 weeks after drug clearance (total abstinence) from the insulin preparation or sulfonylurea in use, but ideally, if feasible and if time on > 12 weeks, washout = drug clearance + time on (e.g., if finishing up a 6 month or 24 week course of glimepirid (duration of activity = 6 days), request bloodwork for serum IGF-I after 25 weeks without any administration of glimepirid; if this is impracticable, then, after 13 weeks without any administration of glimepirid.

6. Estrogens & Progestins (e.g., ethylestrenol, norgestrel): Data Needed; since these hormonal (e.g., contraceptive) agents reduce bioavailable IGF-I by increasing IGF-binding protein 1 (IGFBP-1), thereby unleashing GH secretion by feedback withdrawal – inducing a state of GH resistance – it is imperative that they are totally washed out from to establish a valid base-line serum IGF-I. The General Rule + an additional 10 days applies, formulation-dependently, to theoretically counter the unknown duration of biological activity of IGFBP-1.

Application:

If stopping all agents that affect IGF-I levels at the same time, then the agent that requires the longest washout period dictates the total duration of washout. That is, these agents affect IGF-I in parallel rather than in series, such that the user may wash out from all agents synchronously (at the same time) rather than one after another.

So, I'm assuming the purpose of getting a baseline Igf level is to better understand how certain compounds may be affecting your Igf levels in the future. I just had another round of blood work done myself, although not washed out, I was a little surprised that my Igf levels went down. Especially since I was on GH and my GH levels tested through the roof at 26! Previously without being on GH I tested at 231 Igf and on GH I tested at 167

. Just a little strange but I’m not too worried about it.

Type-IIx · Oct 6, 2023

Keefs said:
So, I'm assuming the purpose of getting a baseline Igf level is to better understand how certain compounds may be affecting your Igf levels in the future. I just had another round of blood work done myself, although not washed out, I was a little surprised that my Igf levels went down. Especially since I was on GH and my GH levels tested through the roof at 26! Previously without being on GH I tested at 231 Igf and on GH I tested at 167 . Just a little strange but I’m not too worried about it.

That's the purpose, yes, to be able to quantify and measure your response with respect to IGF-I to drugs like rhGH, aromatizing AAS, slin, etc.

There is a known decrement to IGF-I after 5-6 mo on rhGH. By 9 months, IGF-I really drops substantially at the same rhGH dose vs. 7-8 mo earlier.

If you're on a low dose like 1.5 - 2.5 IU/d you're probably just pissing away cash, since the increase to IGF-I is basically a proxy for the rhGH efficacy.

Keefs · Oct 6, 2023

I’ve been running 5iu 5-6 times a week. I took a blood test last week 2.5 hours after taking 10iu and these were the results. I’ve heard that you can’t go by igf1 levels to determine if your GH is real which is why I ordered the hgh test also.