If endogenous thyroid peaks at night/early am, why do we take exogenous during the day?

[Gianluca]

According to this study, Thyroid level are at the highest between 10pm and 10am, why then everyone takes it during the day? wouldn't make sense to take the first dose at night before bed, and second right after waking up? I may want to try this actually.

Free Triiodothyronine Has a Distinct Circadian Rhythm That Is Delayed but Parallels Thyrotropin Levels​

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Abstract​

Context: TSH is known to have a circadian rhythm, but the relationship between this and any rhythm in T4 and T3 has not been clearly demonstrated.
Objective: With a view to optimizing thyroid hormone replacement therapy, we have used modern assays for free T4 (FT4) and free T3 (FT3) to investigate circadian rhythmicity.
Setting: The study was performed at a university hospital.
Design and Subjects: This was a cross-sectional study in 33 healthy individuals with 24-h blood sampling (TSH in 33 and FT4 and FT3 in 29 individuals) and cosinor analysis.
Results: Of the individuals, 100% showed a sinusoidal signal in TSH, for FT4 76%, and for FT3 86% (P < 0.05). For FT4 and FT3, the amplitude was low. For TSH the acrophase occurred at a clock time of 0240 h, and for FT3 approximately 90 minutes later at 0404 h. The group cosinor model predicts that TSH hormone levels remain above the mesor between 2020 and 0820 h, and for FT3 from 2200–1000 h. Cross correlation of FT3 with TSH showed that the peak correlation occurred with a delay of 0.5–2.5 h. When time-adjusted profiles of TSH and FT3 were compared, there was a strong correlation between FT3 and TSH levels (ρ = 0.80; P < 0.0001). In contrast, cross correlation revealed no temporal relationship between FT4 and TSH.



Conclusions: FT3 shows a circadian rhythm with a periodicity that lags behind TSH, suggesting that the periodic rhythm of FT3 is due to the proportion of T3 derived from the thyroid. Optimizing thyroid hormone replacement may need to take these rhythms into account.

Free Triiodothyronine Has a Distinct Circadian Rhythm That Is Delayed but Parallels Thyrotropin Levels

Abstract. Context: TSH is known to have a circadian rhythm, but the relationship between this and any rhythm in T4 and T3 has not been clearly demonstrated

academic.oup.com

 

[Guided_by_Voices]

For me, I got a racing heartbeat at night when I first started taking it, so I take it first thing in the morning so that it is hopefully out of my system at night and won't disrupt my sleep. I assume that what my body makes is doing the job at night.

 

[Gianluca]

For me, I got a racing heartbeat at night when I first started taking it, so I take it first thing in the morning so that it is hopefully out of my system at night and won't disrupt my sleep. I assume that what my body makes is doing the job at night.

Are you taking NDT?

 

[Vince]

For me it's a lot easier taking it in the morning. Normally when I go to bed my stomach isn't empty. I do take a few supplements before bed. Which I wouldn't be able to if I was taking my thyroid meds. I take my thyroid meds before I actually get out of bed cuz I know I can't eat or drink anything for 1 hour besides water.

 

[Gianluca]

For me it's a lot easier taking it in the morning. Normally when I go to bed my stomach isn't empty. I do take a few supplements before bed. Which I wouldn't be able to if I was taking my thyroid meds. I take my thyroid meds before I actually get out of bed cuz I know I can't eat or drink anything for 1 hour besides water.

You only take one dose of Thyroid in the am or dive it throughout the day? NDT I would think

 

[Vince]

You only take one dose of Thyroid in the am or dive it throughout the day? NDT I would think

Morning, I take my armor and 6.25 mcg t3 and around 2:00 p.m. I take another round of 6.25 MCG of t3.