Fight the flab

Item No.
12.9 oz / 366 g
Retail Value
Preferred Customer/Associate Price

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Product Information


Sometimes when you lose weight, you’re also losing precious muscle. Fight flab and maintain lean muscle with our clinically proven OsoLean whey protein supplement that can help you sustain a high metabolism and body strength.

Our delicious and all-natural OsoLean powder helps:

  • You lose fat while maintaining lean muscle.*
  • Improve lean mass-to-fat ratio.*
  • You feel full.*


What is OsoLean powder? What ingredients are in OsoLean powder?

The OsoLean powder is a specially formulated whey protein blend that includes an advanced protein peptide technology, which helps the body burn fat while maintaining lean muscle.*

How is OsoLean powder different from ordinary whey protein?

Most whey protein is simply that—whey. In developing OsoLean powder, Mannatech secured a proprietary process where specific parts of whey protein, called peptides, are separated and concentrated to ensure the optimal level of fat-loss peptides.* Mannatech’s OsoLean powder also contains the glyconutrient sialic acid, a sugar found in glycoproteins.

What is the Mannatein® blend?

The Mannatein blend is the proprietary name for our partially hydrolyzed whey protein isolate and whey mineral complex. The OsoLean powder is comprised of this blend and soy lecithin.

How do I use OsoLean powder?

Mix 1 serving (2 scoops) in 8 fluid oz. of liquid or add to food twice daily. For best results, take
OsoLean powder with 8 fluid oz. of liquid 20 minutes before breakfast and 20 minutes before dinner. Our OsoLean powder can be mixed directly into beverages and sprinkled into foods.

What can I mix OsoLean powder in?

The OsoLean powder mixes well with virtually anything. It goes well with beverages such as coffee, milk, meal replacement drinks and fruit juice—even plain water. Our OsoLean powder also mixes well with cereal, yogurt and soups. 

Can I add OsoLean powder to the GlycoSlim drinks?


Does OsoLean powder contain gluten?

Our OsoLean powder is gluten-free.

I’m allergic to casein. Can I use OsoLean powder?

Mannatech’s OsoLean powder is a milk-derived whey protein supplement, but it may contain trace amounts of casein. Testing for the presence of casein has not been performed. Anyone with allergies to casein should discuss use of this product with their personal healthcare professional.

I’m lactose intolerant. Can I take OsoLean powder?

There is a small amount of lactose in OsoLean powder, but it is significantly less than what is found in an eight-ounce glass of milk. Since the effects of lactose intolerance vary with each person, consult your healthcare practitioner with any concerns regarding OsoLean powder.

I have had weight-reduction surgery, can I use OsoLean powder?

Weight-reduction surgery is always very serious. Any changes to diet or exercise, especially those recommended with use of OsoLean powder, should be discussed with your personal healthcare professional who is most familiar with your medical history and current lifestyle program.

Can OsoLean powder be used by pregnant or nursing mothers?

The OsoLean powder is designed for use by adults who want to lose fat and spare lean muscle, when used in conjunction with a reduced-calorie diet and proper exercise.* Due to the high nutritional demands of pregnancy, expectant mothers who wish to use OsoLean powder should discuss its use and the accompanying lifestyle changes with their personal healthcare professional to determine if it is appropriate for them.

Can children use OsoLean powder?

Mannatech’s OsoLean powder was not developed for use by children. If a parent would like for his/her child to use this product, use of OsoLean powder and the accompanying lifestyle changes of calorie reduction and proper exercise should be discussed with the child’s healthcare professional.


Product Information Sheet


Supplement Facts


When combined with a proper diet and exercise.

*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.

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