IsoEnergy Drills 12.8% U3O8 over 9.0m in Drill Hole LE20-54 and Expands Hurricane Zone to the South with Two Strongly Mineralized Holes

High-Grade Uranium Mineralization Continues to Expand and Remains Open to the South and Along Strike to the East for 200m

VANCOUVER, Sept. 17, 2020 - IsoEnergy Ltd. ("IsoEnergy" or the "Company") (TSXV: ISO) (OTCQX: ISENF) is pleased to report additional intersections of strong radioactivity and initial chemical assays from the on-going summer drilling program at the Hurricane zone. The Hurricane zone is a recent discovery of high-grade uranium mineralization on the Company's 100% owned Larocque East property (the "Property") in the Eastern Athabasca Basin of Saskatchewan (Figure 1).

Highlights:

• Chemical assays from drill hole LE20-54 returned 9.0m of 12.8% U₃O₈ and 3.9% Ni from 329.5 to 338.5m, including 4.0m of 27.1% U₃O₈ and 5.2% Ni from 333.0-337.0m,
• South Extension drill hole LE20-62 intersected 4.5m of uranium mineralization (>500 CPS) from 321.0 to 325.5m, including 2.5m of very strong mineralization (>30,000 CPS),
• South Extension drill hole LE20-64 intersected 5.0m of uranium mineralization (>500 CPS) from 324.0 to 329.0m, including 4.0m of very strong mineralization (>30,000 CPS),
• Drill holes LE20-62 and LE20-64 are located on section with, and 11m and 28m (respectively) south of well mineralized drill hole LE20-57 (previously reported),
• LE20-62 and LE20-64 extend mineralization close to the "J" fault, which remains open along-strike to the east for 200m.

Craig Parry, Chief Executive Officer commented: "I want to congratulate our Technical team on these results. The expansion of the Hurricane zone to the south is very encouraging. Our team continues to deliver excellent drilling results efficiently and safely."

Steve Blower, Vice President of Exploration commented: "Our primary objective with the summer drilling program was to extend the zone of intense uranium mineralization to the south on the western side of the Hurricane zone. The results in drill holes LE20-62 and 64 have certainly done that. Importantly, it has now been extended nearly to the "J" fault, which is open along-strike to the east for at least 200m."

LE20-62 Radioactivity (Drill 1)

Drill hole LE20-62 is located 11m south of previously reported drill hole LE20-57, which was well mineralized (Figures 2 and 3). LE20-62 cored strongly altered Athabasca sandstone before intersecting an upper 2.5m thick interval of weak uranium mineralization from 314.0-316.5m, followed by a 4.5m thick interval of strong mineralization from 321.0-325.5m. Included in this interval is 2.5m of intensely radioactive mineralization greater than 30,000 CPS (RS-125), which includes a 0.5m sub-interval that is off-scale on the RS-125 hand-held scintillometer. As with all drill holes to date at the Hurricane zone, the mineralization is located at the sub-Athabasca unconformity. Table 1 summarizes the summer 2020 drilling results to date.

LE20-64 Radioactivity (Drill 1)

Located 17m south of drill hole LE20-62 (Figures 2 and 3), drill hole LE20-64 cored strongly altered Athabasca sandstone before intersecting an upper 3.5m thick layer of weak uranium mineralization from 316.5-320.0m, followed by a 5.0m thick interval of strong mineralization from 324.0-329.0m. Included in this interval is 4.0m of intensely radioactive mineralization greater than 30,000 CPS (RS-125). Mineralization on this north-south section (4435E) now measures at least 48m in width, and is open to the north and south. Most importantly, the summer drilling has now expanded the zone of intense mineralization over 30m to the south, almost to the "J" fault. This fault is parallel to the other main mineralized "H" and "I" faults, and is wide open to the east for at least 200m.

LE20-54 Assays (Drill 1)

Drilled to expand the very strong mineralization intersected in drill hole LE20-32A (8.5m @ 19.6% U₃O₈) during the winter 2020 drill program, drill hole LE20-54 intersected the sub-Athabasca unconformity approximately 7.0m north of winter drill hole LE20-32A (Figures 2 and 4). Radioactivity in drill hole LE20-54 was previously reported. Chemical assays have now been received and the intersection consists of 9.0m of uranium mineralization that averages 12.8% U₃O₈ and 3.9% Ni from 329.5-338.5m. Included in this interval is 4.0m of 27.1% U₃O₈ and 5.2% Ni. Within the higher-grade subinterval is a 0.5m section of off-scale radioactivity that contains 52.5% U₃O₈ and 1.6% Ni.

Other Drill Holes (Drill 2)

Five additional drill holes (LE20-58C1, 59, 60, 61 and 63A) have also been completed with Drill 2 on the eastern side of the Hurricane zone. While all but LE20-60 are weakly mineralized, there have been no intersections of strong uranium mineralization in the holes completed by Drill 2 to date.

Next Steps

Expansion of the Hurricane zone mineralization to the north and south on the western side will remain the primary focus of the program. Samples collected from the drilling completed to date are periodically shipped to the analytical laboratory in Saskatoon. Chemical assay results generally follow within three to four weeks of the shipping dates.

The Larocque East Property and the Hurricane Zone

The 100% owned Larocque East property consists of 31 mineral claims totaling 15,878ha that are not encumbered by any royalties or other interests. Larocque East is immediately adjacent to the north end of IsoEnergy's Geiger property and is 35km northwest of Orano Canada's McClean Lake uranium mine and mill.

Along with other target areas, the Property covers a 15-kilometre-long northeast extension of the Larocque Lake conductor system; a trend of graphitic metasedimentary basement rocks that is associated with significant uranium mineralization at the Hurricane zone, and in several occurrences on Cameco Corp. and Orano Canada Inc.'s neighbouring property to the southwest of Larocque East. The Hurricane zone was discovered in July 2018 and was followed up with 29 drill holes in 2019 and an additional 14 drill holes to date in 2020. Dimensions are currently 575m along-strike, 40m wide, and up to 11m thick. The zone is open for expansion along-strike to the east and on most sections. Mineralization is polymetallic and commonly straddles the sub-Athabasca unconformity 320 m below surface. The best intersection to date is 33.9% U₃O₈ over 8.5m in drill hole LE20-34. Drilling at Cameco Corp.'s Larocque Lake zone on the neighbouring property to the southwest has returned historical intersections of up to 29.9% U₃O₈ over 7.0m in drill hole Q22-040. Like the nearby Geiger property, Larocque East is located adjacent to the Wollaston-Mudjatik transition zone - a major crustal suture related to most of the uranium deposits in the eastern Athabasca Basin. Importantly, the sandstone cover on the Property is thin, ranging between 140m and 330m in previous drilling.

Table 1 – Summer 2020 Drilling Program Results

Qualified Person Statement

The scientific and technical information contained in this news release was prepared by Andy Carmichael, P.Geo., IsoEnergy's Senior Geologist, who is a "Qualified Person" (as defined in NI 43-101 – Standards of Disclosure for Mineral Projects). Mr. Carmichael has verified the data disclosed. All radioactivity measurements reported herein are total gamma from an RS-125 hand-held spectrometer. As mineralized drill holes at the Hurricane zone are oriented very steeply (-70 to -90 degrees) into a zone of mineralization that is interpreted to be horizontal, the true thickness of the intersections is expected to be greater than or equal to 90% of the core lengths. This news release refers to properties other than those in which the Company has an interest. Mineralization on those other properties is not necessarily indicative of mineralization on the Company's properties. All chemical analyses are completed for the Company by SRC Geoanalytical Laboratories in Saskatoon, SK. For additional information regarding the Company's Larocque East Project, including its quality assurance and quality control procedures, please see the Technical Report dated effective May 15, 2019, on the Company's profile at www.sedar.com.

About IsoEnergy

IsoEnergy is a well-funded uranium exploration and development company with a portfolio of prospective projects in the eastern Athabasca Basin in Saskatchewan, Canada. The Company recently discovered the high-grade Hurricane Zone of uranium mineralization on its 100% owned Larocque East property in the Eastern Athabasca Basin. IsoEnergy is led by a Board and Management team with a track record of success in uranium exploration, development and operations. The Company was founded and is supported by the team at its major shareholder, NexGen Energy Ltd.

Neither the TSX Venture Exchange nor its Regulations Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

This news release shall not constitute an offer to sell or a solicitation of any offer to buy any securities, nor shall there be any sale of any securities in any jurisdiction in which such offer, solicitation or sale would be unlawful. The securities referenced herein have not been, nor will they be, registered under the United States Securities Act of 1933, as amended (the "U.S. Securities Act"), and such securities may not be offered or sold within the United States absent registration under the U.S. Securities Act or an applicable exemption from the registration requirements thereunder.

Forward-Looking Information

The information contained herein contains "forward-looking statements" within the meaning of the United States Private Securities Litigation Reform Act of 1995 and "forward-looking information" within the meaning of applicable Canadian securities legislation. "Forward-looking information" includes, but is not limited to, statements with respect to the activities, events or developments that the Company expects or anticipates will or may occur in the future, including, without limitation, planned exploration activities. Generally, but not always, forward-looking information and statements can be identified by the use of words such as "plans", "expects", "is expected", "budget", "scheduled", "estimates", "forecasts", "intends", "anticipates", or "believes" or the negative connotation thereof or variations of such words and phrases or state that certain actions, events or results "may", "could", "would", "might" or "will be taken", "occur" or "be achieved" or the negative connotation thereof.

Such forward-looking information and statements are based on numerous assumptions, including among others, that the results of planned exploration activities are as anticipated, the price of uranium, the anticipated cost of planned exploration activities, that general business and economic conditions will not change in a material adverse manner, that financing will be available if and when needed and on reasonable terms, that third party contractors, equipment and supplies and governmental and other approvals required to conduct the Company's planned exploration activities will be available on reasonable terms and in a timely manner. Although the assumptions made by the Company in providing forward-looking information or making forward-looking statements are considered reasonable by management at the time, there can be no assurance that such assumptions will prove to be accurate.

Forward-looking information and statements also involve known and unknown risks and uncertainties and other factors, which may cause actual events or results in future periods to differ materially from any projections of future events or results expressed or implied by such forward-looking information or statements, including, among others: negative operating cash flow and dependence on third party financing, uncertainty of additional financing, no known mineral reserves or resources, the limited operating history of the Company, the influence of a large shareholder, alternative sources of energy and uranium prices, aboriginal title and consultation issues, reliance on key management and other personnel, actual results of exploration activities being different than anticipated, changes in exploration programs based upon results, availability of third party contractors, availability of equipment and supplies, failure of equipment to operate as anticipated; accidents, effects of weather and other natural phenomena and other risks associated with the mineral exploration industry, environmental risks, changes in laws and regulations, community relations and delays in obtaining governmental or other approvals.

Although the Company has attempted to identify important factors that could cause actual results to differ materially from those contained in the forward-looking information or implied by forward-looking information, there may be other factors that cause results not to be as anticipated, estimated or intended. There can be no assurance that forward-looking information and statements will prove to be accurate, as actual results and future events could differ materially from those anticipated, estimated or intended. Accordingly, readers should not place undue reliance on forward-looking statements or information. The Company undertakes no obligation to update or reissue forward-looking information as a result of new information or events except as required by applicable securities laws

SOURCE IsoEnergy Ltd.