DFND SleepTec Infrared Sleepwear in XXXL: Measured at 6’8″
This is not a set of pajamas. DFND SleepTec is infrared recovery sleepwear, knitted from 50% Celliant Poly and 50% Rayon — a bioceramic fibre meant to take your own body heat and return it as infrared energy. DFND sells to the military, the fire service, first responders and professional athletes before it sells to anyone else, and this line is built for that customer.
Which is what makes the sizing worth writing about. There is no tall size anywhere in the line. DFND confirmed that to me directly, and their own size chart stops at 3XL. A product aimed at a population that skews tall, with nothing above a XXXL.
And yet the long-sleeve shirt is one of the longest garments in my whole database. Both things are true at once.
What I can test, and what I cannot
I measure garments. I cannot measure circulation, so here is the line before anything else.
DFND’s own page says the fabric captures body heat and converts it to infrared energy, and lists the benefits as temperature regulation, temporarily increased local circulation and blood flow, deeper sleep, faster recovery and support for energy and endurance. They say Celliant is backed by nine peer-reviewed clinical studies. Celliant itself reports a 2010 University of California, Irvine pilot — an average 18.3 minutes less awake at night and a 2.6% gain in sleep efficiency — with footnotes stating those results were not achieved by every subject and that further studies are warranted.
The FDA has not approved or designated CELLIANT products for any purpose.
Celliant, on its own website
Alongside that: the determination that these are medical devices was made by Hologenix, Celliant’s own affiliate, and the FDA review referred to was a 513(g) submission — a request for a classification opinion, not an approval. I became a DFND affiliate this month, which is exactly why that paragraph is here rather than left out.
So everything below is fit, length and construction. Whether infrared sleepwear helps you recover is not a question a tape measure can answer, and nothing on this page claims it is.
What the four pieces measure
Taped by hand at 6 foot 8, laid flat and un-stretched. Nothing read off a size chart. The four pieces run roughly $65 to $75 each on DFND’s own site.
| Garment | Size | Chest, flat | Shoulder | Body, back | Sleeve, centre back | Cuff |
|---|---|---|---|---|---|---|
| SleepTec IR LS shirt | XXXL | 27″ | 22.5″ | 33.5″ | 38.5″ | 5″ |
| SleepTec IR SS shirt | XXXL | 27″ | 22.5″ | 31.5″ | 20″ | 9″ |
| Garment | Size | Waist, flat | Waist, stretched | Front rise | Back rise | Inseam | Thigh, flat | Leg opening |
|---|---|---|---|---|---|---|---|---|
| SleepTec IR pant | XXXL | 20″ | 23″ | 14″ | 16″ | 32″ | 14.5″ | 8.5″ |
| SleepTec IR short | XXXL | 21″ | 22.5″ | 14″ | 17″ | 8″ | 15″ | 14.5″ |
The long sleeve is longer than most tall shirts I own
Body length decides a shirt on a long torso, and almost nobody publishes it. The SleepTec long sleeve against tall-labeled garments I have taped myself:
| Garment | Label size | Body length, back |
|---|---|---|
| DFND SleepTec IR LS shirt | XXXL — no T | 33.5″ |
| Under Armour Tech 2.0 half zip | 5XLT | 32″ |
| Under Armour Tech 2.0 half zip | 4XLT | 32″ |
| Under Armour exercise shirt | 3XLT | 32.5″ |
| Under Armour Rival Fleece half zip hoodie | 4XLT | 31.75″ |
| Izod crewneck sweater | 3XLT | 31″ |
| Kohl’s FLX polo | 3XLT | 33″ |
On me it finishes at the bottom of the seat. The usual failure in a sleep shirt is a hem that rides up over the small of your back the moment you lie down; this one has the length not to. The sleeve runs 38.5 inches from center back to cuff, which is long by any measure.
The short sleeve is two inches shorter in the body at 31.5, level with the Under Armour tall shirts rather than above them. If you are buying one of the two for length, buy the long sleeve.
Affiliate links — same price to you.
The pant
The pant is close-fitting rather than loose, so the 32 inch inseam is doing a different job from a cotton pajama bottom — it is meant to end at the ankle, not break over the foot. On me it finishes right above the ankle bone, which is where it should.
It is still a regular inseam on a tall frame, and it is the one place the missing tall size shows. If you are long in the leg rather than long in the torso, this is the piece to think hardest about. The rise is generous — 14 inches front, 16 back — so it suits a long torso better than a long leg.
The short has an 8 inch inseam, sits at the knee, and the 14.5 inch leg opening is generous. Of the two waistbands the pant gives more: 20 inches flat to 23 stretched, against 21 to 22.5 on the short.
Affiliate links — same price to you. DFND listed the pant as sold out at the time of writing; the short was in stock.
The honest summary
- The long sleeve shirt is the piece worth having if you are tall through the torso. It is longer than tall-labeled shirts from brands that do make tall.
- The short sleeve is ordinary by comparison — good, not remarkable.
- The pant fits a long torso better than a long leg. Generous rise, regular inseam.
- The absence of a tall size is the real gap, and it is a strange one in a line built for athletes.
What to measure on the recovery wear you already own
Before ordering in this category, tape the garment you already sleep in and like. Three numbers:
- Body length, back. Base of the collar straight down to the hem. Under 32 inches rides up on a long torso.
- Inseam. Crotch seam to hem. On a close-fitting bottom you want it ending at the ankle, not above it.
- Waist, flat and stretched. Both. The stretched figure is what you actually wear.
Put those into the Fit Finder and it returns every garment I have measured that matches within half an inch. I taped them so you can find what already works instead of ordering and sending it back.
Match these numbers against what you already own →
Buying this for someone tall
DFND have put the line into a holiday gift guide, and two things about it matter more to a tall buyer than the price. There is no tall size, so you are buying the XXXL and hoping — and DFND give ninety days to decide, with exchanges and returns. For a category nobody can try on first, a ninety-day window is the part worth knowing. The long sleeve and the pant sit in the under-one-hundred tier; the compression tight is a tier above that.
Disclosure
DFND supplied these four garments free of charge for review, which makes them gifted under FTC rules, and this page says so plainly. I became a DFND affiliate in October 2026 and every DFND link on this page, including the gift guide, is an affiliate link. Nothing gifted gets an Amazon review from me, because Amazon prohibits incentive reviews. Every measurement above is my own, taken by hand, and would read the same if I had paid for all four.
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