Dosing, Bioavailability, and Human Scaling

The strongest RET-style melatonin claims come from animal and cell studies, not human oncology trials.

That means dose discussion has to separate measured evidence from extrapolated human-equivalent estimates.

If you need the formulation page, go to DIY Liposomal Melatonin.

The two anchor studies

In vivo mouse study

Benaiges et al. used 40 mg/kg intraperitoneal melatonin in tumour-bearing mice.

That exposure suppressed tumour growth and was linked to a transient mitochondrial ROS burst.

In vitro cell study

Florido et al. exposed head-and-neck cancer cells to 0.5 to 1 mM melatonin.

ROS rose within the first 1 to 3 hours, then preceded apoptosis.

The dose-dependent immune split still matters

The source literature points to two very different melatonin use cases.

Moderate adjunct range

This is the human oral oncology range.

It usually means about 10 to 40 mg nightly by mouth.

This range is generally discussed as:

• circadian-supportive

• Th1-supportive or at least Th1-compatible

• compatible with the Lissoni-style adjunct literature

Very high RET-aimed exposure

This is the mechanistic high-exposure range.

It aims at something closer to the mouse-equivalent systemic exposure.

That is where the RET and ROS discussion sits.

It is also where concern about Th1 blunting, broader immunosuppression, sedation, endocrine load, and CYP effects rises.

What counts as a very high pharmacological exposure

The animal-to-human scaling from 40 mg/kg in mice gives about 3.24 mg/kg in humans.

That works out to roughly:

• 160 mg systemic exposure for a 50 kg person

• 230 mg systemic exposure for a 70 kg person

A practical shorthand is a target near 225 mg reaching the bloodstream.

That is an exposure estimate, not a proven human treatment target.

Why oral dose and systemic dose are not the same

What matters mechanistically is not what is swallowed.

What matters is what actually reaches circulation.

Plain powder or standard tablets

If oral bioavailability is near 10%, reaching about 225 mg systemically may require roughly 2 to 2.5 grams swallowed.

Liposomal or alcohol-solubilised liquid

If absorption is closer to 40%, the same systemic target may be reached with roughly 600 mg swallowed.

These are alternative routes to a similar estimated exposure.

They are not meant to be combined.

Practical interpretation

Three practical points matter here.

• Better absorption lowers the total oral dose needed.

• Poor absorption pushes people toward gram-level intake.

• Gram-level intake raises tolerability, sedation, endocrine, and interaction questions much faster.

If only raw powder is used, roughly 2 to 2.5 g may be needed to approach the mouse-equivalent internal exposure.

If a higher-efficiency liposomal or solubilised system is used, the swallowed amount can be much lower.

For formulation context, see DIY Liposomal Melatonin.

Better delivery changes the arithmetic

The key point is that oral dose and internal exposure are not interchangeable.

A better-formulated liquid may reach a target exposure with far less material swallowed.

A poorly absorbed powder may require several times more.

That difference matters because the body responds to both the systemic exposure and the burden of the formulation used to get there.

Gram-level powder is a different practical problem

Swallowing 2 to 2.5 grams of plain powder is not just a dosing calculation.

It creates a separate tolerability question.

Sedation, gastrointestinal tolerance, product quality, and interaction risk all become more relevant at that scale.

This is one reason the route and formulation question cannot be treated as a minor detail.

The uncertain middle zone

One practical problem is the range between classic human adjunct use and estimated mouse-equivalent systemic exposure.

Someone can sit well above the 20 to 40 mg nightly human range without clearly reaching the exposure that the RET argument is built on.

That middle zone is hard to interpret with confidence.

It may be too low for the intended mitochondrial pulse logic, yet high enough to move outside the better-supported adjunct window.

A practical example is 400 mg plain powder orally.

That may still fall well short of the estimated systemic RET target while moving above the classic oral human adjunct range.

What can and cannot be claimed

The current evidence supports three careful claims.

• Mouse and cell studies support a high-exposure ROS mechanism.

• Human oral adjunct studies support a moderate-dose clinical-support zone.

• The bridge between those two worlds remains extrapolated.

Caveats that matter

1. Route matters. Intraperitoneal mouse dosing is not the same as oral human dosing.

2. Formulation matters. Liposomal and solubilised products vary widely.

3. Absorption varies. Gut handling, food, and product quality change real exposure.

4. Side effects scale up. Sedation, endocrine shifts, and CYP1A2 interaction risk become more relevant at higher intakes.

5. The immune trade-off matters. Higher exposure is not automatically better if the goal is Th1 support.

Bottom line

The high-dose mitochondrial model is exposure-driven.

The current human discussion is therefore about approximation, not confirmation.

That is why moderate clinical adjunct use and very-high-dose RET-style use should be treated as two different strategies.

Related pages

• Melatonin in Oncology - Study Notes — the hub page that ties together the mitochondria, dosing, immune, phase-separation, and fibrosis sections

• DIY Liposomal Melatonin — formulation notes, storage, costing, and practical liposomal-delivery context

• High-Dose Mitochondria, RET, and ROS — the mechanistic RET, ROS, uncoupling, and apoptosis sequence behind the high-dose claim

• Moderate-Dose Immune Effects and Timing — the human oral adjunct literature, Th1 logic, and timing framework

• Phase Separation in Oncology — the oncogenic-condensate model, its three levers, and the chronotherapy angle

• Fibrotic Drivers and the 26-Gene Signature — how the condensate story overlaps with EMT, fibrosis, YAP/TAZ, β-catenin, and stromal remodelling

• Addendum — Dosing, Th1/Th2, and Recalibration — why continuous high-dose oral use may work against the immune goal, and how to reassess it

Key references

• Benaiges et al. 2023
  https://pmc.ncbi.nlm.nih.gov/articles/PMC5884151/

• Florido et al. 2022
  https://pmc.ncbi.nlm.nih.gov/articles/PMC9404709/