How to start a fitness clothing line that performs and pays

The steps

1. Pick one activity and one hero product. Hot yoga, heavy lifting and distance running each punish fabric differently, so a line that tries to serve all three at launch ends up serving none of them well. Most fitness labels open with one piece they can be known for, a legging, a sports bra or a training short, in a few core colors, and add tops once the hero sells through.
2. Choose the fabric before you finish the design. In activewear the knit is most of the product. Decide the fiber pair (nylon and spandex is usually softer and smoother; polyester and spandex usually costs less and takes sublimation print), the hand (brushed, matte, sleek or ribbed) and the weight, then ask for the fabric's specification sheet and test reports with the quote. The table below lists what to ask for.
3. Decide how custom the first run is. Adapting a factory's proven legging pattern in your fabric and colors, the private label route, needs fewer sample rounds than cutting your own pattern. Cut and sew makes sense when fit is the reason your brand exists.
4. Write the tech pack with the activewear details. Beyond what every garment needs (the tech pack guide covers that), spell out the seam type (flatlock or coverstitch, so nothing chafes), the gusset shape, waistband height and construction, any bonded or laser-cut edges, pocket placement for a phone, and the grade rules. Stretch fabric is patterned smaller than the body, so write the finished measurements you want, not body measurements.
5. Sample, then wear-test like a customer. Do squats in the leggings under bright light to check that the fabric stays opaque at full stretch. Train in the sample, wash it several times, and look for pilling between the thighs, seams that pop, waistbands that roll and a sports bra that lets the wearer bounce. Fit every sample on more than one body in your size range, because a knit that fits a sample-size model can go sheer or tight at the ends of the range.
6. Get the fiber label and hang tags right. Performance fabrics blend fibers in ways the textile rules speak to directly. The section below has the details.
7. Keep finish claims inside the rules. Odor control, water repellency and compression are the three selling points that carry legal limits. Settle each claim before the factory prints the hang tag.
8. Size the first order to the minimums. Factories usually quote an MOQ per style per color, and a custom fabric color can carry the mill's own minimum on top. Stock colors from the mill's range, black first, keep the first order small, and ask what the minimum becomes if you commit to a reorder.
9. Price it landed and choose the country on that price. Synthetic leggings, shorts and tees carry about twice the general duty rate of the same garments in cotton, so compare quotes with duty, freight and fees included, as shown further down.

What to ask for on the fabric

If no test results come with the quote, have the bulk fabric tested before cutting. It costs far less than a run of leggings that goes sheer.

Fiber labels and hang tags for performance fabrics

Stretch knits almost always contain spandex, and US labels name it by its generic fiber name. The FTC recognizes the international name too: the ISO standard uses elastane for spandex^[2], and you may use either word on your label.

Leggings usually contain enough spandex to name it outright. A performance tee may carry only a trace, and the textile rules normally fold a fiber under the small-amount threshold into "other fiber". They still allow it to be named when it has a clearly established and definite functional significance^[3] at that amount, which stretch does.

Performance fibers are often sold with their own trademarked names, and brands like to put them on a hang tag. That is allowed, but when the garment contains other fibers too, the tag must disclose clearly and conspicuously that it does not provide the product's full fiber content^[4], with wording such as "See label for the product's full fiber content." Put that line on the hang tag artwork in your tech pack.

Customs looks at the stretch fiber as well. The statistical lines under women's synthetic knit trousers split out garments 5 percent or more by weight of elastomeric yarn or rubber thread^[1], so the spandex percentage in your tech pack also decides the statistical number your broker declares at entry.

Odor control, water repellency and compression: the claims with limits

Anti-odor and antimicrobial finishes. A fabric treated with an antimicrobial can be sold without its own EPA registration under the treated articles exemption, but only for a use intended to protect only the treated article or substance itself^[5], meaning the fabric. A garment that relies on that exemption must not make public health claims, such as "fights germs, provides antibacterial protection, or controls fungus"^[5], and the preservative claim gets no greater prominence than other described product features^[5]. EPA's own example of an acceptable label says the antimicrobial properties are built in to inhibit bacteria that may affect the product, and that they do not protect users against bacteria, viruses or germs. Write odor claims about the fabric in that shape; "kills germs" or "antibacterial protection" for the wearer is out. Ask which antimicrobial the fabric is treated with and whether it is registered for textile use.

Water-repellent and stain-resistant finishes. Many of these finishes are PFAS chemistry, and state law is starting to ban them in clothing. New York^[6], for one, bars the sale of new apparel containing intentionally added PFAS after January 1, 2025^[6], and its list of covered clothing names tops, leggings, leisurewear^[6]. Outdoor apparel for severe wet conditions has a later deadline. After January 1, 2028^[6], a separate restriction applies to it. A store that stocks your line can rely on a certificate of compliance, signed by an authorized official of the manufacturing company^[6]. Under the law the manufacturer includes the company whose brand name is affixed to apparel^[7], so that certificate is yours to sign, and it is a violation of this section to provide a certificate of compliance^[7] for garments that do not meet the limits. Specify "no intentionally added PFAS" in the tech pack, and get that commitment in writing, for the fabric as well as the finished garment, before you order, since you will sell into every state from one inventory.

Compression. Compression that describes fit ("sculpting", "firm hold") is a fabric feature. Compression sold as a health treatment can make the garment a medical device: the FDA classifies a medical support stocking as a device that is constructed of elastic material and designed to apply controlled pressure to the leg^[8]. What counts is intended use, which the FDA says can be shown by labeling claims, advertising matter, or oral or written statements^[9]. Leave out claims about circulation, recovery from injury or swelling unless you are prepared to meet the device rules.

Why synthetic activewear costs more to land

The general duty rate depends on the garment type and the fiber that predominates by weight, and for leggings, shorts and tees the synthetic lines cost about twice as much as the cotton ones. Sports bras pay one rate whatever the fiber.

These are general rates, charged on the customs value, before any additional duties on goods from a particular country. Those additional duties change often and differ by origin, so check them for each country you are quoting before you choose; the import duty guide shows how the layers stack. Men's and women's garments sit in separate headings, so have your broker classify each style.

What a first run of leggings costs landed

600 nylon and spandex leggings, 3 colors of 200, made overseas

Line	Amount
Production: 600 units at $9.80 FOB the origin port	$5,880.00
General duty at 28.2%[1] of the production price	$1,658.16
Additional duty for the country of origin at 10% (assumed)	$588.00
Ocean freight (shared container) and insurance	$650.00
Customs broker and entry fees	$350.00
Trucking from the port to your warehouse	$300.00
Landed cost of the run	$9,426.16
Landed cost per legging	$15.71
Samples, three rounds, with courier	$540.00
Lab tests on the bulk fabric	$450.00
Total with development	$10,416.16
Cost per legging with development	$17.36

The same run in a cotton-rich knit would pay general duty at 14.9%^[10], or $876.12, which is $782.04 less, about $1.30 a legging. It would also be a different product: cotton holds sweat, which is why performance leggings are synthetic.

Illustrative figures, not a quote. Real prices depend on the spec, quantity and factory.

The general duty alone is about a sixth of the landed cost in this example, more than freight, broker and trucking together. That is why the country you make in and the fiber you choose move your margin more than a small difference in the factory price.

Quotes for a fitness line

Send us the tech pack, the fabric you have in mind (or the properties from the fabric table above) and your colors and quantities per style, and we introduce you to activewear manufacturers that fit, overseas first, and name each one, or tell you if none does. Introductions are free for brands, and each manufacturer quotes you directly, so ask each manufacturer to state its Incoterms rule on the quote and set it straight against a landed cost like the one above and your retail price.