What is going on with my T4? Declining since I started HGH

[kaizoku]

Can anyone explain what's going on with my bloodwork?

Had blood drawn yesterday and just got partial results back that show low T4.
Over the past year my T4 has been declining, right about the same time I started HGH.

April 2024: T4 = 6.4mcg/DL Free T4 Index 2.0, TSH 1.56 mIU/L (2 months on HGH)

September 2024: 6.1mcg/DL Free T4 Index 2.1, TSH 1.47 mIU/L

February 2025: 5.5mcg/DL Free T4 Index 1.7, TSH 1.38 mIU/L

April 2025: 4.1mcg/DL (Low) Free T4 Index 1.6, TSH 1.22 mIU/L (14 months on HGH)

A week before my latest bloodwork I went on a work trip and had to drop the HGH for 5-6 days.
Before the trip I was taking 3.5iu of Opti greys and starting to get CTS sides (hands/arms falling asleep in bed).
When I came back I decided to drop the dose to 2.5iu and start titrating back up to try to reset and avoid sides.
No diet changes and no cycle changes between February 2025 and April 2025 other than adding 15-30mg var back in, which I was on for the
September 2024 bloodwork.

I've been feeling tired and sluggish since I got back and started back up on HGH.

I've always felt really hot, have trouble cooling down after a shower or any physical activity, excessively sweaty after physical activity and T4 has always been in mid-6 range. Nothing has changed since my T4 declined other than feeling more tired.

Going to recheck bloods in 6 weeks or so but wondering if this is something I need to be concerned about.
Do I need to start supplementing T4?

 

[Trenbolonetax]

Can anyone explain what's going on with my bloodwork?

Had blood drawn yesterday and just got partial results back that show low T4.
Over the past year my T4 has been declining, right about the same time I started HGH.

April 2024: T4 = 6.4mcg/DL Free T4 Index 2.0, TSH 1.56 mIU/L (2 months on HGH)

September 2024: 6.1mcg/DL Free T4 Index 2.1, TSH 1.47 mIU/L

February 2025: 5.5mcg/DL Free T4 Index 1.7, TSH 1.38 mIU/L

April 2025: 4.1mcg/DL (Low) Free T4 Index 1.6, TSH 1.22 mIU/L (14 months on HGH)

A week before my latest bloodwork I went on a work trip and had to drop the HGH for 5-6 days.
Before the trip I was taking 3.5iu of Opti greys and starting to get CTS sides (hands/arms falling asleep in bed).
When I came back I decided to drop the dose to 2.5iu and start titrating back up to try to reset and avoid sides.
No diet changes and no cycle changes between February 2025 and April 2025 other than adding 15-30mg var back in, which I was on for the
September 2024 bloodwork.

I've been feeling tired and sluggish since I got back and started back up on HGH.

I've always felt really hot, have trouble cooling down after a shower or any physical activity, excessively sweaty after physical activity and T4 has always been in mid-6 range. Nothing has changed since my T4 declined other than feeling more tired.

Going to recheck bloods in 6 weeks or so but wondering if this is something I need to be concerned about.
Do I need to start supplementing T4?

What is your free T3?

Are you seeing an elevation in that?

GH increases the conversion of T4 to T3. If you see your fT4 go down, and your fT3 go up on GH, that's pretty normal. There is difference of opinion on when or if there should be intervention.

I typically will use enough T4 to keep my ft4 in range. This happens to me on GH doses 6 - 8iu+ i'll start to supplement T4. 100mcg seems to be a good place for me.

 

[kaizoku]

I've been using PrivateMDLabs Medium Hormone Panel, which doesn't include Free T3. I need to start adding that to my labs.

 

[Ghoul]

Can anyone explain what's going on with my bloodwork?

Had blood drawn yesterday and just got partial results back that show low T4.
Over the past year my T4 has been declining, right about the same time I started HGH.

April 2024: T4 = 6.4mcg/DL Free T4 Index 2.0, TSH 1.56 mIU/L (2 months on HGH)

September 2024: 6.1mcg/DL Free T4 Index 2.1, TSH 1.47 mIU/L

February 2025: 5.5mcg/DL Free T4 Index 1.7, TSH 1.38 mIU/L

April 2025: 4.1mcg/DL (Low) Free T4 Index 1.6, TSH 1.22 mIU/L (14 months on HGH)

A week before my latest bloodwork I went on a work trip and had to drop the HGH for 5-6 days.
Before the trip I was taking 3.5iu of Opti greys and starting to get CTS sides (hands/arms falling asleep in bed).
When I came back I decided to drop the dose to 2.5iu and start titrating back up to try to reset and avoid sides.
No diet changes and no cycle changes between February 2025 and April 2025 other than adding 15-30mg var back in, which I was on for the
September 2024 bloodwork.

I've been feeling tired and sluggish since I got back and started back up on HGH.

I've always felt really hot, have trouble cooling down after a shower or any physical activity, excessively sweaty after physical activity and T4 has always been in mid-6 range. Nothing has changed since my T4 declined other than feeling more tired.

Going to recheck bloods in 6 weeks or so but wondering if this is something I need to be concerned about.
Do I need to start supplementing T4?

rHGH can suppress TSH, reducing T4 production. It looks like your TSH is steadily dropping while T4 goes
down (T4 should be going up when TSH goes down).

But it also increases sensitivity to T4, somewhat offsetting the reduction.

Are you having any symptoms like weight gain, lethargy, sensitivity to cold?

 

[Trenbolonetax]

I've been using PrivateMDLabs Medium Hormone Panel, which doesn't include Free T3. I need to start adding that to my labs.

If you'll be pulling regular labs, you may look into a fitomics subscription. It substantially reduces the price of labs and makes it quite affordable to run large panels frequently.

I was a completely lazy and plugged this into Perplexity. If you haven't checked out the book, Bolus, by TypeIIx, I definitely would highly recommend if you plan to leverage GH now and in the future, or secretagogues.

@TypeIIx's analysis of recombinant human growth hormone (rhGH) and its impact on thyroid hormone conversion emphasizes both mechanistic insights and clinical risks. Here's a synthesis of their perspective:

### Key Mechanisms
- **Peripheral T4-to-T3 Conversion**: rhGH increases the peripheral conversion of free thyroxine (fT4) to active triiodothyronine (fT3), a process often misinterpreted as beneficial in bodybuilding circles. However, this conversion reflects a derangement in thyroid regulation rather than an improvement in function[1][4].
- **Lipolysis Link**: The lipolytic effects of rhGH are partially mediated by this enhanced T4-to-T3 conversion, which upregulates mitochondrial uncoupling proteins (UCP2/UCP3) to elevate resting metabolic rate[4][6].

### Clinical Implications
1. **Central Hypothyroidism**:
- rhGH does not directly cause hypothyroidism but can *unmask* preexisting central hypothyroidism, particularly in individuals with structural pituitary abnormalities (e.g., tumors, congenital defects)[1][4].
- In such cases, rhGH exacerbates diminished IGF-I responses and blunts TSH secretion, worsening thyroid dysfunction[1].

2. **Thyrotoxicosis Risk**:
- Prolonged supraphysiological rhGH use may induce symptoms of hypothyroidism (e.g., cold intolerance, dry skin) or mild thyrotoxicosis (e.g., palpitations, anxiety) due to dysregulated T3 levels[4][6].

3. **Bodybuilding Misconceptions**:
- Elevated fT3 levels are erroneously celebrated as "optimal" in bodybuilding, despite representing a pathological state. Chronic rhGH use disrupts hypothalamic-pituitary-thyroid axis feedback, potentially leading to long-term metabolic complications[1][4].

### Practical Takeaways
- **Monitoring**: Users with pituitary abnormalities or on long-term rhGH should regularly assess thyroid function (fT3, fT4, TSH) and watch for hypothyroid symptoms[1][4].
- **Dose Considerations**: While rhGH’s T3-boosting effect aids fat loss, excessive doses or prolonged use may outweigh benefits by destabilizing thyroid homeostasis[4][6].

In summary, @TypeIIx frames rhGH-induced T4/T3 conversion as a double-edged sword: metabolically advantageous in the short term but potentially harmful in predisposed individuals or with unmonitored use.

Citations:
[1] Women and GH: dosages, effects of estradiol, IGFBP-1
[2] T3 vs T4 , which is the healthiest option
[3] Distinction between Prolactin and Progestins [by Type-IIx]
[4] The Definitive Thyroid Hormone Thread (T3, T4, some implications for rhGH)
[5] T3 vs T4 , which is the healthiest option
[6] The Definitive Thyroid Hormone Thread (T3, T4, some implications for rhGH)
[7] https://thinksteroids.com/community...tion-after-stopping-t4.134410611/post-2976966
[8] https://thinksteroids.com/community/threads/hgh-length.134409247/page-2
[9] How long for HGH and IGF-1 to Return to Baseline?
[10] https://thinksteroids.com/community/threads/why-you-should-be-running-t4-with-your-gh.134386686/
[11] Adding T4 to GH
[12] https://thinksteroids.com/community...-that-is-science-based.134408038/post-3392444
[13] TrenboloneTax: Hybrid Cycling / Lifting Log aka Make Hulk Bike Fast
[14] Experienced gh users question.
[15] https://thinksteroids.com/articles/unique-effects-of-metandienone-dianabol/
[16] Aussie Male Labs Comments Please
[17] Are you guys running T4/T3 with your HGH?
[18] https://thinksteroids.com/community...stic-handbook-downloads.134282198/post-660782
[19] T4 on gh
[20] https://thinksteroids.com/community/threads/clen-and-atenolol-or-nebivolol.134412864/
[21] https://thinksteroids.com/community...k-and-loosing-strength.134420337/post-3304160
[22] A GH and fat loss protocol (rhGH lipolysis) that is science-based
[23] Human Growth Hormone and Peptides
[24] T3 and t4 usage in a bulk
[25] https://www.ugbodybuilding.com/threads/why-use-t-4-vs-t3-with-a-growth-cycle.40342/
[26] The Definitive Thyroid Hormone Thread (T3, T4, some implications for rhGH)
[27] T4 with GH?
[28] No longer feeling DNP work towards the end?
[29] T4 with HGH for contest prep , who does it
[30] What valid role does T4 have with HGH?
[31] The Definitive Thyroid Hormone Thread (T3, T4, some implications for rhGH)
[32] T3 and T4 dosing “sweet spot”
[33] What valid role does T4 have with HGH?
[34] HGH and T3 help

---
Answer from Perplexity: pplx.ai/share

 

[kaizoku]

rHGH can suppress TSH, reducing T4 production. It looks like your TSH is steadily dropping while T4 goes
down (T4 should be going up when TSH goes down).

But it also increases sensitivity to T4, somewhat offsetting the reduction.

Are you having any symptoms like weight gain, lethargy, sensitivity to cold?

Just lethargy.

I actually have the opposite and have a sensitivity to heat...the slightest amount of physical activity and I get hot, start sweating buckets and take forever to cool down, have been like this since long before I ever started on gear.

 

[Ghoul]

Just lethargy.

I actually have the opposite and have a sensitivity to heat...the slightest amount of physical activity and I get hot, start sweating buckets and take forever to cool down, have been like this since long before I ever started on gear.

My take on it is that while your levels are within the normal range, free t4 is dropping, so it may be low for *you*.

It's my understanding that despite still being with the wide "normal range", if hypothyroid symptoms have developed some doctors will treat with levothyroxine. As long as you keep free T4 within the normal range, symptoms like fatigue are getting better, and you aren't experiencing hyperthyroid symptoms, it's a low risk approach.

The normal starting dose of T4 is 1.6mcg/kg. However under the circumstances I think starting slow is a much better idea:

If you think the fatigue has been increasing while ft4 has been dropping, if I were in your shoes I'd get some pharma (NOT UGL) t4 50mcg and 25mcg (it's cheap AF, ~$4 / 120 tabs), then start at the "extra cautious" dose of 50mcg and see how it goes for a couple of weeks. If you're feeling better, and numbers are still in range, you could increase by 25mcg and reassess after a few weeks. You could keep going until you're at the 80th percentile free t4 for your age, or stop short of that if you're experiencing hyperthyroid symptoms (jittery, excessive weight loss).

 

[Boss Brady 12]

Listen to this guy he has been here for a month and already ELITE!! He must know everything in