This study is a 8-week, randomized, double-blind, placebo-controlled clinical trial of Silk Peptide for the evaluation of efficacy on immune function enhancement.

This study will evaluate Silk Peptide's efficacy on immune function in healthy volunteers who white blood cells count is in between 4000/㎕ and 8000/㎕ by assessing improvements in certain immune indices (i.e. NK cell activity, IFN-γ, TNF-α, IL-1β, 2, 12, IgG1, IgG2).

Inclusion Criteria:

1. Adult male and female volunteers over 50 years
2. Screening result for WBC counts in between 4,000 cells/ul and 8,000 cells/ul
3. Volunteers who have agreed to participate in the study and provided a written content by him/herself or through its legal representative

Exclusion Criteria:

1. Those with a history of drug and clinically significant hypersensitivity reactions
2. Those with thyroid or pituitary disease
3. Those with acute severe cardiovascular disease such as heart failure, myocardial infarction, and stroke
4. Those with immune system disease or severe liver failure, kidney failure or history
5. Those with a history of systemic diseases such as malignancy, lung disease, leukemia, collagenosis, multiple sclerosis, allergic skin disease and other autoimmune diseases
6. Those with a BMI of less than 18.5 kg/m2 at screening
7. Those diagnosed with diabetes
8. Those with a history of gastrointestinal disorders (ex. Crohn's disease) or gastrointestinal surgery (excluding simple appendectomy or hernia surgery) that may affect the absorption of clinical trial products
9. Those who have consumed medicines, healthy functional foods within 2 weeks before screening or are currently consuming health supplements that can affect immune function. (For health functional foods, they can participate through 1 week before the first intake day.)
10. Those who have received antipsychotic medication within 2 months before screening
11. Those with a alcoholism or history of substance abuse
12. Those who participated in other clinical trials within 2 months before screening
13. Those who are pregnant, breastfeeding
14. Fertile women who do not accept the appropriate method of contraception (except for women who have undergone sterilization operation)
15. Those who are deemed inappropriate by the researcher